FOREWORD 



Information is scanty relative to mean settling velocities of sand 

 samples from natural beaches. Nevertheless, for many studies it is 

 desirable to obtain measurements of the mean still-water settling veloc- 

 ities of natural aggregates of sand-sized material because the settling 

 velocity of an individual particle in quiescent water is the most 

 fundamental hydraulic characteristic that can be measured. This study 

 was designed to measure and record the systematic variations in mean 

 settling velocity of a large number of sand samples taken simultaneously 

 along three transects across a natural beach and in the area around the 

 mouth of an inlet associated with the beach. 



Results of the measurements of mean settling velocities presented 

 in this technical memorandum are for quiescent water of the temperature 

 encountered during sampling and the derived dynamic properties of mean 

 Reynolds number and mean drag coefficient are also for an infinite column 

 of quiescent sea water at the natural temperature. The various dynamic 

 properties are tabulated and a set of curves is presented so that the mean 

 settling velocities observed for the natural water temperature (6.9°) can 

 be converted to settling velocities at any water temperature between 0° 

 and 36° C. 



This report was prepared by Dr. Wyman Harrison, Associate Marine 

 Scientist of the Virginia Institute of Marine Science, in pursuance of 

 Contract DA-49-055-CIVENG-63-6 with the Beach Erosion Board, and in 

 collaboration with Mr. Reinaldo Morales-Alamo, a graduate student at the 

 Institute . 



This report is published under authority of Public Law 166, 79th 

 Congress, approved July 31, 1945, as supplemented by Public Law 172, 

 88th Congress, approved November 7, 1963. 



